Wheel-track gauge for motor vehicles



2 Sheets-Sheet l D. W. HAIR WHEEL-TRACK GAUGE FOR MOTOR VEHICLES .lnim viw Aug. 18, 1959 Filed Dec g- 18, 1959 D. w. HAIR WHEEL-TRACK GAUGE FORMOTOR VEHICLES 2 Sheets-Sheet 2 Filed Dec. 4, 1957 United States Patent2,899,753 WHEEL-TRACK GAUGE FOR MOTOR VEHICLES Douglas Walter Hair, NewPlymouth, New Zealand Application December 4, 1957, Serial No. 700,643

Claims priority, application New 'Zealand, December 4, 1956 8 Claims.(Cl. 33-20321) The invention relates to a gauge for use in tracking thefront wheels of motor vehicles so that the wheels shall be in trueparallelism or shall have the correct amount of toe-in or toe-outaccording to the makers recommendations.

Hitherto the operation of retracking the front wheels of motor vehiclesfor correct alignment has been regarded as a task that should be carriedout only by specialists if extreme accuracy is required. Precisionequipment enabling such accuracy to be obtained is expensive andconsequently is available only in a relatively few service garages whichspecialize in retracking operations.

For use by small service garages there is on the market a portabletracking gauge having a wobble-plate in the form of a shallow ramp on towhich a front wheel of a vehicle is run and which, under the action ofthe wheel, serves to move a pointer over a scale according to the angleof approach of the wheel as it passes onto the plate. This gauge is notvery satisfactory in use, firstly because it necessitates repeatedmovement of the vehicle to cause the wheel to roll onto and off theplate while adjustments to the track connections are being made, andsecondly because the final result is still somewhat uncertain andspeculative.

The object of the present invention is to provide, for the purpose inquestion, a gauge which is of simple form, can be manufactured and soldat a moderate price, is easy to use, enables the retracking operation tobe carried out with precision and speed and without the need for a highdegree of skill, and is otherwise of such construction that it can bereadily made available to all service garages and stations as part ofthe normal equipment.

A gauge when constructed in accordance with one embodiment of theinvention is illustrated in the accompanying drawings, in which:

Figure 1 is a plan view of the complete gauge;

Figure 2 is an edge view looking in the direction of the arrow II inFigure 1;

Figure 3 is a fragmentary plan view illustrating a portion of the gaugeto an enlarged scale;

Figure 4 is an end view corresponding to Figure 3;

Figure 5 is a plan View of another part of the gauge to a scale greaterthan that of Figures 1 and-2 but smaller than that of Figure 3 and 4;

Figure 6 is a fragmentary sectional view on the line VI-VI of Figure 5;V

Figure 7 is a sectional View on the line VII-VII of Figure 5;

Figure 8 is a plan view corresponding to a portion of Figure 1, butshowing how the parts of the gauge may be conveniently placed togetherwhen the gauge is not in use;

Figure 9 is an outside elevational view of one of the steerable wheelsof a vehicle, showing how the gauge is used, and

Figure 10 is a plan view, partlyin section, corresponding to Figure 9.

2,899,753 Patented Aug. 18, 1959 As shown in the drawings, the'g'augecomprises a frame generally indicated at 1 and including a front tubularbar 2 and a rear tubular bar3, these bars being spacedpal'rallelly witheachother and joined at their ends to tubular arms 4 arranged atright-angles to the bars 2 and 3. "The arms 4 extend from the bar 2 to apoint lying rearwardly of the bar 3 so that the frame 1 is. generally ofreclining U-shape as shown most clearly in Figure .1. The bars z and 3are reinforced by two transverse members 5 which are spaced from eachother and on the uppersurfaces of which there are secured a total offour iron platforms 6 for a purpose to bedescribed.

Fora purpose also to be described, the portions of the arms 4 extendingrearwardly of the bar 3 are-fitted with oppositely disposedandinwardly'projecting stubs 7 -'the free ends of which are cha'mferedasindicated at 7a in Figures 1 and 2. I

Preferably, and as shown in Figures 1 and 8, the frame 1 is made oftelescopic form so that the distance between the arms 4 can be increasedand decreased according to requirements. To this end, the bars 2 and 3are made up of outer tubes joined to one of the two arms 4, and innertubes fitting closely but slidably in the outer tubes and joined to theother one of the two arms 4, the inner tubes being indicated at 2a and3a respectively.

Over the two corners where the bar 2 joins the arms 4- there are securedscale plates 8, each plate being marked with graduations extending fromthe. rear edge of the plate. As clearly shown in" Figure 3, each set of.graduations includes a zero or central point and lines lying on eitherside of that point and respresenting degrees of toein and toe-outincreasing by increments of, say, one sixteenth of an inch between oneline and the next. The plates 8 are held in position by screws 8a whichpass through slots 8b in the plates, thereby enabling the plates to beadjusted for correct centre during assemblyof the gauge.

For use in conjunction with the scale plates 8 there are providedpointers 9 extending along the upper surfaces of the arms, each pointerbeing marked with a longitudinally extending centre-line 10 The pointers9 are pivotally connected at their rear ends to the rear end parts ofthe arms 4 by means of pivot pins'll, while'the forward ends of thepointers are sharpened as indicated at 9a and lie close to thegraduations marked'on the scale plates 8. With this arrangement, thepointers 9 can be swung in a horizontal plane about the axes of thepivot pins 11 so that the sharpened ends 9a of the pointers move alongthe graduations on the scale plates 8. When the pointers 9 are'sopositioned that the centre lines =10 thereon are in exact register withthe Zero pointson the scale plates 8, the lines 10 will be inexactparallelism with one another, while when the pointers'are swungoutwardly or inwardly of-thosei pointsgthe lines 10'will diverge from orconverge towards one another, thus ygiving ameasure of toe-in or toe-outwhen considered in conjunction with the graduations on thescale platesSMeans are provided for frictionallyholding the pointers 9 againstmovement when they have been swung-t0 their selected positions. To thisend, there are provid ed small helical springs 12 (Figures 2 and 4)acting between upper and lower washers 13 (Figures 3 and-4) arrangedaround screws 14 which pass freely through slots 15 extending across thepointers 9, the screws being threaded into the arms4. The springs 12 actto pressthe pointers 9 resiliently down upon the arms 4 so that thepointers are held by sufficient friction to prevent them moving out ofplace of their own accord once they have been set in selected positions,

For use in conjunction with the frame 1 there a'r eipro vided twoidentical comparison bars 16 made'from nonopening 23 formed in the bar.

magnetic metal such as aluminium. The bars 16 are of approximately thesame length as the arms 4 of the frame 1 and, as shown most clearly inFigures 5 to 7, each bar is formed with a straight edge 17 and with twoflat faces 18 and 19 spaced from each other and lying in parallelismwith the straight edge 17, the face 19 being longer than the face 18.

Each comparison bar is fitted with two permanent horse-shoe magnets 20and 21.

The magnet 20 fits against the face 18 of the bar 16, being sopositioned that its two pole-pieces extend away from the face, and isheld rotatably but frictionally in this position by a screw 22 (Figures1 and 5) which passes through a hole in the face 18 and projects into anThe part of the screw 22 lying within the opening 23 is fitted with ahelical spring 24 which is maintained in compression between a washer 25and a nut 26 on the screw.

The magnet 21 fits against the face 19 of the bar 16, being again sopositioned that its two pole-pieces extend away from the face. In thisinstance, the magnet 21 is mounted for both a rotatable and a slidingmovement relatively to the face 19. For this purpose, the magnet iscarried by a screw 27 which passes freely through a slot 28 (Figures 5,6 and 7) formed in and extending along the face 19, and projects into anelongated opening 29 formed in the bar 16. The part of the screw 27lying within the opening 29 is fitted with a helical spring 39 which isheld in compression between a washer 31 and a nut 32 on the screw 27.With this arrangement, the magnet 21 can be rotated about the axis ofthe screw 27 and can also be moved along the bar 16 so as to vary thedistance between this magnet and the magnet 20. The

friction set up between the magnet 21 and the face 19 under the actionof the spring 30, is sufiicient to hold the magnet in the position towhich it has been adjusted.

The open ends of the arms 4 and stubs 7 may be plugged to prevent theingress of dirt.

For checking the front wheel alignment of a motor vehicle and enablingany necessary adjustments to be made for parallelism, or for toe-in ortoe-out, according to the makers specification, the gauge is used asfollows, reference now being made more particularly to Figures 9 andWith the aid of the graduations on one of the scale plates 8, thecorresponding pointer 9 is set so that its centre-line 10 is broughtinto exact register with the zero point on this scale plate. With theaid of the graduations on the other scale plate, the correspondingpointer is set in accordance with the correct setting of the frontwheels as recommended by the makers. For example, if the makersrecommend a toe-in of one-eighth of an inch, the second pointer is setso that the centre-line thereon comes into register with the graduationon the adjacent scale plate which indicates one-eighth of an inchinwardly of the zero, or true parallelism, point.

With the front wheels 33 (Figures 9 and 10) of the vehicle instraight-ahead position as judged by the eye or by any marking that themakers may have provided on the steering wheel, the frame 1, while lyingflat on the ground in front of the vehicle, is pushed towards the frontwheels so that the portions of the arms 4 extending rearwardly of thebar 3 are brought to a position in which they lie adjacent the outsidesof the two wheels 33 (see Figure 10), while the bar 3 is brought to aposition in which it has even contact with the treads of the tyres ofthe Wheels (see Figure 9). In this position of the bar 3, the inner endsof the stubs 7 have contact with the outer walls of the tyres wherethese come close to the ground, the stubs thus acting to centralise theframe relatively to the wheels 33. The inner ends 7a of the stubs 7, bybeing chamfered, allow for the natural bulge of the tyres and thus fitsnugly against the outer side walls thereof.

Where the frame 1 is of telescopic form as already described, it isexpanded before being presented to the wheels 33 and thereaftercontracted so as to bring the inner ends 7a of the stubs 7 into contactwith the outer side walls of the tyres, the frame then being suitablefor application to different makes of vehicles in which the distancebetween the front wheels varies from one make to another.

With the frame in position as explained, the comparison bars 16 arepresented, magnets 20 and 21 foremost, to the outsides of the rims 34 ofthe wheels 33, the bars being held so that they extend horizontallyacross the hubs and preferably a little below the axis of rotation ofthe wheels. While each comparison bar is so held, the magnets 20 and 21are partly rotated and the magnet 21 is moved along its face 19 so thatwhen the bar is in final position, the two magnets will fit snuglyagainst the inturned part of the rims 34, one magnet lying forwardly andthe other rearwardly of the axis of rotation of the wheel as shown inFigures 9 and 10. As soon as the magnets are brought into contact withthe rim at horizontally spaced points as just described, they will, bymagnetic attraction, adhere to the rim, and thus serve to hold the bar16 in position against the wheel to which it has been applied. By reasonof the fact that the magnets 20 and 21 of each bar 16 are in trueparallelism with the straight edge 17 of the bar, they will, when matedwith the same part of the rim 34 but at spaced horizontal points asexplained, ensure that the straight edge 17 will give a true indicationof the setting of the wheel in the direction of movement of the vehicle.

As the magnets 20 and 21 of both bars 16 serve to hold the bars againstthe rims 34 only by magnetic attraction, any slight adjustment to themagnets and bars that may be necessary to ensure that the bars arecorrectly applied, can be made while the bars are in attached position.

Now that the bars 16 have been applied, a steering movement is nowapplied to the wheels 33 so that the wheel lying adjacent the pointer 9that was set at zero position, is brought to true straight aheadposition, this latter position, being determined by looking downwardlyalong the straight edge 17 of the corresponding comparison bar 16 andcomparing this edge with the centre line 10 on the pointer. If thestraight edge 17 is seen to be in true coincidence with the centre line10, it will be known that the wheel is, in fact, in a truestraight-ahead position. If the eye observes any divergency, thesteering wheel can be manipulated until true coincidence is observed.

As soon as the first wheel has been set in straightahead position, asight is taken downwardly along the straight edge 17 of the comparisonbar on the other wheel, this edge being compared with the centre line 10on the corresponding pointer 9. If the edge and the line are in truecoincidence, it will be known that both wheels are correctly set. Ifthere is any divergence, adjustments are made to the tie-rod connectionsforming part of the steering mechanism of the vehicle, until coincidenceis established.

The mode of use of the gauge as described in the foregoing is notnecessarily invariable. When, for example, the wheels 33 have to be setfor a particular amount of toe-in or toe-out and the vehicle is fittedwith double tie-rods, the total amount may be divided equally betweenthe two pointers 9, each wheel then being in dividually adjusted aftersighting the straight edge 17 of the associated comparison bar 16against the centre line 10 of the corresponding pointer 9.

Figure 8 shows a convenient way of assuring that the comparison bars 16will not become mislaid when the gauge is not required for use. For thispurpose, the bars are placed so that they bridge the gap between thetransverse members 5 of the frame 1, the magnets 20 and 21 thenadhering, by magnetic attraction, to the iron platforms 6 on the members5. In this way, the 'bars 16 become attached to the frame, thus.enabling the gauge as a whole to be hung up out of the way in aconvenient place.

Within the scope of the invention certain modifications arecontemplated, such modifications rendering the gauge suitable for use inthe assembly line of a factory in which motor vehicles are manufacturedor assembled.

In one such modification and where the factory produces vehicles inwhich the setting of the front wheels is always the same, the arms 4 maybe permanently set to indicate true parallelism, or in-toe, or out-toe,according the specified setting for the wheels, the scale plates 8 andpointers 9 then being dispensed with and the comparison bars 16 thenbeing used in conjunction with the arms themselves, or with centre linemarkings thereon, to indicate the specified setting.

In another modification, the frame 1 may consist merely of the bar 3 andthe arms 4, the bars being fixed to the floor at that part of theassembly line where the wheel-tracking operation is performed, and thearms being represented by markings applied to the floor, the markingsbeing, if necessary, graduated to allow for differing designs ofvehicles passing along the line. In the interests of permanency, themarkings, including any necessary graduations, may be constituted bymetal strips let into the floor so that their upper edges are visible.The upper edges may, if desired, project slightly above the floor sothat they are always readily distinguishable.

What I claim is:

l. A wheel-track gauge for motor vehicles, comprising a frame havingparallelly arranged tubular bars spaced from each other in a horizontalplane, and one of which can be placed against the treads of thesteerable wheels of the vehicle; a first arm extending at right-anglesto the said bars and joined to one end thereof; a second arm alsoextending at right-angles to the said bars and having laterallyprojecting members engaged slidably in the other end of the said bars;pointers mounted on and extending along the said arms, the pointersbeing pivotally connected at one end to the arms so that their oppositeends can be moved in relation to graduation markings on the frame, eachpointer being provided with a longitudinally disposed line; and twocomparison bars having straight edges and fitted with spaced magnets forengagement with the rims of the steerable wheels at opposite sides ofthe axes thereof so that the comparison bars will then be held to therims by magnetic attraction, thus allowing the straight edges of thecomparison bars to be sighted in conjunction with the lines on thepointers, for comparing angles.

2. A wheel-track gauge in accordance with claim 1, and wherein theparallelly arranged tubular bars consist of a front bar and a rear bar,the said arms extending from the front bar to a point lying rearwardlyof the rear bar.

3. A wheel-track gauge in accordance with claim 2. and wherein theportions of the said arms extending rearwardly of the rear tubular barare formed with oppositely disposed and inwardly projecting stubs.

4. A wheel-track gauge in accordance with claim 2 and wherein the frontand rear tubular bars are reinforced by transverse members spaced fromeach other and on the upper surfaces of which there are provided ironplatforms with which the magnets on the comparison bars can be engaged.

5. A wheel-track gauge in accordance with claim 1 and wherein means areprovided for frictionally retaining the pointers in the selectedpositions relatively to the graduation markings on the frame.

6. A wheel-track gauge in accordance with claim 1 and wherein eachcomparison bar is formed with two flat faces spaced from each other andlying in parallelism with the straight edge of the said bar, a permanentmagnet being applied against each of the said faces and connected to thebar.

7. A track gauge in accordance with claim 6 and wherein the said magnetsare of the horse-shoe type and are mounted for rotation on said flatfaces.

8. A track gauge in accordance with claim 6 and wherein one of themagnets is mounted for movement towards and away from the other magnet.

References Cited in the file of this patent UNITED STATES PATENTS1,138,736 Dedreux May 11, 1915 1,449,289 King Mar. 20, 1923 2,000,993Schmidt May 14, 1935 2,285,965 Halstead June 9, 1942 2,556,227 Shaw June12, 1951 2,577,841 Creagmile Dec. 11, 1951 2,616,186 Shooter et al. Nov.4, 1952

